| Abbreviation | Definition |
|---|---|
| ACSO | Allen County Sheriff's Office |
| ACTC | Alameda County Transportation Commission |
| ACTID | Athens County Transportation Improvement District |
| ACTL | Aiken County Technology Laboratory |
| ACTR | Addison County Transit Resources |
| ACTS | Ashtabula County Transportation Systems |
| ACUA | Atlantic County Utilities Authority |
| ACVL | All Counties Vehicle Logistics |
| ACWC | Arts Council for Wyoming County |
| ACWC | Arts Council of Williamson County |
| ACWD | Alameda County Water District |
| ACWWA | Arapahoe County Water and Wastewater Authority |
| ACWWA | Arapahoe County Water and Wastewater Authority's |
| ACWWA | Arapahoe County Water Wastewater Authority |
| ACYW | Austin County Youth Wrestling |
| ACZO | Arlington County Zoning Ordinance |
| ADLC | Anaconda Deer Lodge County |
| ADOC | Affiliated Doctors of Orange County |
| AFCS | Atlanta–Fulton County Stadium |
| AHCB | Atlas of Historical County Boundaries |